Heparin-induced thrombocytopenia, part 2: Clinical course and treatment. How can drug selection help spare life and limb?

Increasing evidence indicates that management of "isolated" heparin-induced thrombocytopenia (HIT) should include substitution of heparin by an alternative anticoagulant, such as danaparoid, lepirudin, or argatroban. Usually, one of these agents is given in therapeutic doses until platelet count recovery has occurred. Because of delays in obtaining HIT antibody test results, the initial decision to stop heparin and give an alternative agent generally is made on clinical grounds. There are important treatment paradoxes in the management of HIT-associated thrombosis. For example, prophylactic platelet transfusions are relatively contraindicated in HIT, since bleeding is uncommon and platelets theoretically could contribute to increased thrombotic risk. Use of an oral anticoagulant for deep venous thrombosis complicating acute HIT can cause microvascular thrombosis leading to limb loss. However, warfarin can be used for long-term anticoagulation, provided it is initiated following substantial platelet count recovery and during overlap with an alternative anticoagulant.